1. cars burning fossil fuels2.

1. cars burning fossil fuels
2. cars shredding micro-particles of their tires on roads while driving and flinging them into the air
3. capitalists entrapping people into cars by requiring them drive into work
4. car companies lobbying municipalities to fund car infrastructure over trains
5. federal tax incentives to fund car infrastructure
6. car culture, a "dominant culture", persuading entire populations that owning cars is good and dissuading nay-sayers

this is why we have Alteimers Disease
https://abcnews.com/US/air-pollution-emerges-direct-risk-factor-alzheimers-disease/story?id=130220279